Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D295/00—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms
  • C07D295/16—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms acylated on ring nitrogen atoms
  • C07D295/20—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms acylated on ring nitrogen atoms by radicals derived from carbonic acid, or sulfur or nitrogen analogues thereof
  • C07D295/205—Radicals derived from carbonic acid
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
  • A61P9/12—Antihypertensives
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D239/00—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings
  • C07D239/70—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings condensed with carbocyclic rings or ring systems
  • C07D239/72—Quinazolines; Hydrogenated quinazolines
  • C07D239/95—Quinazolines; Hydrogenated quinazolines with hetero atoms directly attached in positions 2 and 4

Definitions

• the invention relates to an improved process for preparing the 2-methyl-2-hydroxypropyl piperazine-1-carboxylate moiety of certain preferred quinazoline derivatives which are useful antihypertensive agents.
• this moiety is a member of a large class of 2-position substituents of quinazoline antihypertensive agents which are described in the following U.S. Pat. Nos.: 3,980,650, 3,935,213, 3,769,286, 3,669,968, 3,663,706, 3,635,979 and 3,511,836.
• the quinazoline agents possessing this moiety are mentioned in the '286, '968 and '706 patents as being especially interesting because they have a high degree of hypotensive activity.
• isobutylene carbonate is required for the synthesis of the 2-methyl-2-hydroxypropyl piperazine-1-carboxylate side chain.
• its reaction with amine is capable of producing two isomers. Hence it would not be expected to provide an effective route to the desired antihypertensive agents because of significant contamination with the unwanted structural isomer.
• the conditions of the reaction process are as follows. If the piperazine compound and isobutylene carbonate are reacted without solvent, a neat melt is used covering temperatures from one at which the isobutylene carbonate and piperazine compound are in the liquid state to one about at which the isobutylene carbonate or piperazine compound refluxes or decomposes. Although the actual temperature required to produce the liquid state will vary somewhat with the identity of the piperazine compound, a temperature range of about 65° to about 185° or reflux will usually produce the liquid state and avoid decomposition. If the piperazine compound and isobutylene are reacted in a polar, protic solvent, the temperature must be within the range of from ambient to reflux. If the piperazine compound and isobutylene carbonate are reacted in a polar or nonpolar, aprotic solvent, the temperature must be at least about 70° to reflux.
• Some appropriate polar, protic solvents are water, methanol and ethanol. Some polar or nonpolar, aprotic solvents are acetonitrile, dimethylformamide, diethylformamide, dimethylacetamide, diphenyl ether, bis(2-methoxyethyl)ether, benzene and mono-, di-, and trimethyl benzene.
• the invention also includes two other methods for preparing the 2-methyl-2-hydroxypropyl carboxylate compound.
• the first method involves rearrangement of the 1,1-dimethyl-2-hydroxyethyl 4-substituted-piperazine-1-carboxylate structural isomer. According to this method, the structural isomer or a gross mixture of it and the 2-methyl-2-hydroxypropyl carboxylate compound is maintained at a temperature of at least about 70° C. in a polar or nonpolar, aprotic solvent or at ambient to reflux temperature in polar, protic solvent until essentially pure carboxylate compound is produced.
• the second method involves only the preparation of 2-methyl-2-hydroxypropyl piperazine-1-carboxylate.
• isobutylene carbonate and piperazine are combined, a competing side reaction can form the bis adduct. It is usually avoided by using excess piperazine but any undesired bis adduct contaminant may be converted to the desired carboxylate compound by refluxing in excess piperazine.
• the important features of the process are as follows. If the piperazine compound and isobutylene carbonate are reacted in a polar, protic solvent such as water, methanol, ethanol and the like, the temperature must be in the range of ambient to reflux. If the piperazine compound and isobutylene carbonate are reacted in polar or nonpolar, aprotic solvent, the temperature must be at least about 70° C. to reflux. Suitable polar or nonpolar aprotic solvents are acetonitrile, dimethylformamide, diethylformamide, dimethylacetamide, diphenyl ether bis-2-(methoxyethyl)ether, benzene, mono-, di- and trimethyl benzene and the like.
• a polar, protic solvent such as water, methanol, ethanol and the like.
• a neat melt covering temperatures cover the range from the point at which the isobutylene carbonate and piperazine compound are in the liquid state to the point about which the isobutylene carbonate or piperazine compound refluxes or decomposes.
• the neat melt reaction will be run at temperatures from about 65° to about 185° or reflux which will be sufficient to put the reaction in the liquid state.
• the time required to produce the desired essentially pure carboxylate compound depends upon the type of solvent and temperatures used. In general enough time must be allowed to establish thermodynamic equilibrium. Therefore it is common to monitor the increase in concentration of the desired carboxylate compound relative to the structural isomer and stop the reaction when there is no further increase. In common practice about 30 min. to about 240 min. will be sufficient to produce essentially pure carboxylate compound.
• the sequence of mixing of the starting materials in the neat reaction or the solution reaction is unimportant. They both may be present in the reaction pot before it is heated or the amine may be heated to the appropriate reaction temperature and then the isobutylene carbonate may be added.
• any mixture containing the bis adduct or the isolated bis adduct itself may be refluxed in piperazine while monitoring the production of the carboxylate compound.
• the bis adduct competing side reaction can be minimized or avoided by using excess piperazine compound. It is usual practice to use about a 2 to 3 molar equivalent excess.
• the progress of the reaction can be monitored by any sampling technique that will establish the relative concentrations of the carboxylate compound and the structural isomer.
• the ratio of the 2-methyl-2-hydroxypropyl carboxylate compound to the 1,1-dimethyl-2-hydroxyethyl structural isomer can be determined by comparing respective NMR absorptions of the gem dimethyl groups.
• Other techniques such as high pressure liquid chromatography, thin layer chromatography and gas chromatography may also be used to establish the relative amounts of the two isomers.
• the reaction may be considered to have reached thermodynamic equilibrium when the carboxylate compound is shown by such an analysis to be essentially free of the structural isomer, i.e., when the ratio of carboxylate compound to structural isomer is at least 95 to 5. In usual practice there will be no detectable structural isomer.
• Isolation of the desired carboxylate compound can be accomplished by the usual methods. For example, partitioning the reaction mixture between aqueous and organic layers, the aqueous layer being acidified if appropriate, and taking the necessary steps to isolate the residue from the selected partition layer followed by recrystallization of the residue will surffice. Another method involves crystallizing the desired carboxylate compound directly from the nonpolar, aprotic solvent used in the reaction.
• the compounds prepared by the process of the invention are substituted quinazoline medicinal agents or are intermediates which are transformed to the medicinal agents by known methods as described above.
• the process allows the preparation of the intermediates or the agents in high yields using inexpensive, non-toxic starting materials and does not rely upon phosgene.
• Examples 1 through 6 show that the process of the invention achieves the synthesis of the desired 2-methyl-2-hydroxypropyl carboxylate compound which is essentially free of the structural isomer. NMR analysis indicates that a gross mixture of the two isomers is kinetically formed but as the process continues the desired carboxylate compound is thermodynamically produced in an essentially pure state.
• the following examples are merely illustrative and in no way limit the scope of the appended claims.
• the IR spectral data were obtained on a diffraction grading infrared spectrometer and are given in cm -1 .
• the NMR spectral data were obtained on a Varian T-60 spectrometer and are given in delta ppm.
• the temperatures of the reactions described in the Examples are bath temperatures and are uncorrected. When the temperature is unspecified, it will be taken to mean ambient or room temperature which varies from 15° to 30° C.
• the gummy residue was treated with ethanolic hydrogen chloride and the precipitated hydrochloride of the title compound (11) was recrystallized from chloroform/methanol/isopropyl ether: m.p. 236°-239°.
• the free base title compound (11) was obtained from the hydrochloride by the standard usual procedures and recrystallized from methanol/ethyl acetate, m.p. 201°-3° C.
• the dynamic ratio of the yield of the tertiary (1) to primary (2) alcohol with respect to time was estimated from the relative intensities of the NMR absorptions of the gem dimethyl groups of the tertiary alcohol ( ⁇ 1.23 ppm) and the primary alcohol ( ⁇ 1.38 ppm). The relation is shown below.

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• Organic Chemistry (AREA)
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• Animal Behavior & Ethology (AREA)
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• Bioinformatics & Cheminformatics (AREA)
• Medicinal Chemistry (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• General Chemical & Material Sciences (AREA)
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• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
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Citations (5)

• 1979
  • 1979-03-08 DK DK095979A patent/DK153878C/da active
  • 1979-03-08 IN IN166/DEL/79A patent/IN151190B/en unknown
  • 1979-04-17 CH CH360979A patent/CH638796A5/fr not_active IP Right Cessation
  • 1979-05-03 BG BG7943441A patent/BG31228A3/xx unknown
  • 1979-05-04 HU HU79PI675A patent/HU180282B/hu unknown
  • 1979-05-04 SU SU792763448A patent/SU1007557A3/ru active
  • 1979-05-05 PL PL1979215383A patent/PL118664B1/pl unknown
  • 1979-05-06 CS CS793161A patent/CS236762B2/cs unknown
  • 1979-05-07 RO RO7997441A patent/RO76812A/ro unknown
  • 1979-05-07 DD DD79212699A patent/DD143428A5/de unknown
  • 1979-05-15 EG EG288/79A patent/EG13904A/xx active
  • 1979-05-15 YU YU1139/79A patent/YU41633B/xx unknown
  • 1979-05-16 DE DE2919799A patent/DE2919799C2/de not_active Expired
  • 1979-05-16 GR GR59103A patent/GR72720B/el unknown
  • 1979-05-16 NO NO791641A patent/NO151156C/no unknown
  • 1979-05-16 GB GB7916996A patent/GB2021107B/en not_active Expired
  • 1979-05-16 IL IL57295A patent/IL57295A/xx unknown
  • 1979-05-16 AU AU47102/79A patent/AU510441B2/en not_active Expired
  • 1979-05-16 CA CA327,766A patent/CA1097643A/en not_active Expired
  • 1979-05-16 SE SE7904313A patent/SE446183B/sv not_active IP Right Cessation
  • 1979-05-16 PH PH22498A patent/PH15546A/en unknown
  • 1979-05-16 LU LU81271A patent/LU81271A1/xx unknown
  • 1979-05-17 NL NLAANVRAGE7903892,A patent/NL183190C/xx not_active IP Right Cessation
  • 1979-05-17 JP JP54060999A patent/JPS5946512B2/ja not_active Expired
  • 1979-05-17 AT AT0366579A patent/AT375357B/de not_active IP Right Cessation
  • 1979-05-17 ZA ZA792391A patent/ZA792391B/xx unknown
  • 1979-05-17 NZ NZ190473A patent/NZ190473A/xx unknown
  • 1979-05-17 PT PT69623A patent/PT69623A/pt unknown
  • 1979-05-17 BE BE0/195204A patent/BE876311A/xx not_active IP Right Cessation
  • 1979-05-17 MX MX797985U patent/MX6289E/es unknown
  • 1979-05-17 FI FI791579A patent/FI64588C/fi not_active IP Right Cessation
  • 1979-05-17 GT GT197957903A patent/GT197957903A/es unknown
  • 1979-05-17 ES ES480669A patent/ES480669A1/es not_active Expired
  • 1979-05-17 FR FR7912569A patent/FR2432022A1/fr active Granted
  • 1979-05-17 IT IT22759/79A patent/IT1114238B/it active
  • 1979-05-18 AR AR276570A patent/AR220195A1/es active
  • 1979-08-08 IE IE962/79A patent/IE48048B1/en not_active IP Right Cessation
  • 1979-09-17 FR FR7923128A patent/FR2429788A1/fr active Granted
• 1980
  • 1980-02-07 PH PH23617A patent/PH16236A/en unknown
• 1981
  • 1981-04-24 US US06/257,365 patent/US4550164A/en not_active Expired - Lifetime
• 1983
  • 1983-11-02 SG SG65783A patent/SG65783G/en unknown
  • 1983-11-22 KE KE3353A patent/KE3353A/xx unknown
• 1984
  • 1984-02-16 HK HK134/84A patent/HK13484A/xx not_active IP Right Cessation
• 1985
  • 1985-12-30 MY MY95/85A patent/MY8500095A/xx unknown
• 1987
  • 1987-01-15 DK DK019587A patent/DK153880C/da not_active IP Right Cessation
  • 1987-01-15 DK DK019487A patent/DK153840C/da not_active IP Right Cessation
  • 1987-01-15 DK DK019387A patent/DK153879C/da active
  • 1987-01-15 DK DK019687A patent/DK153881C/da active
  • 1987-01-15 DK DK019287A patent/DK19287D0/da not_active Application Discontinuation

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